Identification, cloning and sequencing of Escherichia coli strain χ1378 (O78:K80) iss gene isolated from poultry colibacillosis in Iran


T. Zahraei Salehi, Department of Microbiology, Faculty of Veterinary Medicine, University of Tehran, Qareeb Street, Azadi Av. PO Box: 14155-6453, Tehran, Iran. E-mail:


Aims:  To identify, clone and sequence the iss (increased serum survival) gene from E. coli strain χ1378 isolated from Iranian poultry and to predict its protein product, Iss.

Methods and Results:  The iss gene from E. coli strain χ1378 was amplified and cloned into the pTZ57R/T vector and sequenced. From the DNA sequence, the Iss predictive protein was evaluated using bioinformatics. Iss from strain χ1378 had 100% identity with other E. coli serotypes and isolates from different origins and also 98% identity with E. coli O157:H7 Iss protein. Phylogenetic analysis showed no significant different phylogenic groups among E. coli strains.

Conclusions:  The strong association of predicted Iss protein among different E. coli strains suggests that it could be a good antigen to control and detect avian pathogenic E. coli (APEC).

Significance and Impact of the study:  Because the exact pathogenesis and the role of virulence factors are unknown, the Iss protein could be used as a target for vaccination in the future, but further research is required.